I think you're missing a key piece of information in either SW or FW, which is that if the tank is cycled, there should be NO ammonia present. The ammonia that's being produced would be turned into nitrite and then into nitrate, and nitrate is the only thing you'd find with any value at all. So, there's something wrong with biological filtration here, because you state that you're doing the weekly water change to remove ammonia and nitrate, when, in fact, you should have no ammonia at all. It's true that no one has to have a doctorate to own fish tanks, but there is still a lot of knowledge that has to be acquired, and this is very basic information. I'd definitely start doing some research. If you have the biological cycle working for you, converting ammonia and nitrite to nitrate, your experience is going to be much more enjoyable. In order to have that happen, you'll need to really look into your filtration and tank maintenance and figure out what's wrong with the bio.
Edit: The article that SpeshulEd recommends is excellent, as well. Definitely take the time to look over it!